Quaternary ammonium salts of oxygen containing strong sulfur acids in the cation of which there are no more than two aryl groups and one group having a methacrylyloxy substituent



Patented May 4, 1954 UNITED STATES PATENT OFFICE Arthur L. Barney,Wilmington, DeL, assignor to E. I. du Pont de Nemours and Company,Wilmington, DeL, a corporation of Delaware No Drawing. ApplicationJanuary 21, 1952, Serial No. 267,495

Claims. 1

This invention relates to a new class of polymerizable vinyl compoundsand more particu larly to certain monomeric quaternary ammonium vinylcompounds.

Basic addition polymers and copolymers have recently become ofindustrial significance, par ticularly since they offer a ready means ofpreparing shaped objects, e. g., films and fibers, which are readilydyeable, in contrast to the extremely poor dyeability and aqueousprocessing response exhibited by many synthetic polymers containing nobasic groups. More recently, as described, for instance, in thecopending application of Barney Serial No. 216,838, filed March 21,1951, it has been discovered that the quaternary salts of the basictertiary amino copolymers are particularly outstanding in that they notonly exhibit the superior dyeability and aqueous processing response ofthe basic amino copolymers, but at the same time exhibit a thermalinsensitivity only slightly less than the outstanding thermalinsensitivity of the polymers containing no basic groups.

One method of preparing these new quaternary copolymers involves thecopolymerization of a tertiary amino-containing monomer with therequisite comonomer, followed by after-quaternization of the tertiaryamino group with the requisite quaternizing agent. However, this finalquaternization step is far from clean-cut or straight-forward since itinvolves chemical reaction on a polymer. For instance, the control ofthe amount of basic tertiary amino groups converted to the desiredquaternary groups is by no means as good as is desired. Furthermore, anyunreacted quaternizing agent, the removal of which is extremelydifficult, is quite detrimental to the over-all properties of thepolymer, particularly the important thermal stability. Final- 1y, due tothe nature of some of the more desirable quaternizing agents,particularly their hydrolytic instability, and in many instances thesolubility properties of the starting basic tertiary amino polymers, thequaternization reaction cannot be carried out in aqueous systems andtherefore necessitates the use of the more expensive organic solventswhich are generally more difiicult to remove and, in many instances,because of their potential inflammability, add appreciably to theindustrial hazards involved.

This invention has as an object the provision of new polymerizablequaternary ammonium monomers. intermediates for polymers and copolymers.Other objects will appear hereinafter.

These objects are accomplished by the present invention of quaternaryammonium salts wherein the quaternary ammonium nitrogen is joined to theanion of an oxygen-containing strong sul fur acid of ionization constantgreater than 1 l0 and to a monovalent hydrocarbon radical having onesubstituent and that a Z-methyleneacyloxy radical, the remainingvalences of the quaternary nitrogen being satisfied by hydrocarbonradicals with the said quaternary ammonium nitrogen directly bonded toat most two aromatic carbons. Because of the greater availability of therequisite intermediates the 2- methylenealkanoyloxyalkanetrihyd r o c ar b o a m monium salts of the oxygen-containing strong sulfur acids arepreferred. These new quaternary monomers can be readily prepared byquaternization of the requisite Z-methyleneacyloxyhydrocarbodihydrocarbotertiary amine with the requisite hydrocarbo ester of the necessaryoxygen-containing sulfur acid. Suitable acids of ionization greater than1 10 are: sulfuric acid, sulfurous acid, and the hydrocarbosulfonicacids, e. g., the alkyl-, aryl-, aralkyl-, alkaryl-, andcycloalkylsulfonic acids.

The new polymerizable Z-methyleneacyloxy quaternary ammonium saltmonomers of this invention wherein the anion is that ofanoxygencontaining strong sulfur acid are readily and easily prepared inhigh yields and high states of purity. These new quaternary ammoniummonomers are readily polymerizable and copolymerizable, particularlywith acrylonitrile in conventional addition polymerization systems,including aqueous solutions or dispersions, to give good yields of highmolecular Weight filmand fiber-forming polymers, particularly theacrylonitrile copolymers which exhibit thermal insensitivities onlyslightly less than the outstanding thermal insensitivity ofpolyacrylonitrile and at the same time exhibit superior dyeability andaqueous processing response. In this connection, these new2-methyleneacyloxy quaternary ammonium salts of oxygen-contain ingstrong sulfur acids are particularly out- Another object is theprovision of standing in comparison with the corresponding halogenquaternary salts since they crystallize so readily and are so much lesshygroscopic that they can easily be purified to the extremely high levelof purity necessary for successful addition polymerization.

The following examples in which parts are by weight are illustrative ofthe invention.

EXAIVIPLE I Preparation of beta-methacryZyloxyethyltrimethylammom'umcycloheranesulfonate To a stirred. solution of 52.5 parts ofbeta-dimethylaminoethyl methacrylate in about 80 parts of methyl ethyllretone cooled in an ice/water bath is added under anhydrous conditionsover a period of one hour a solution of 59.5 parts of methylcyclohexanesulfonate in about 80 parts of methyl ethyl ketone. Thereaction mixture is held at 32-35 F. for one week and the resultantsolid then removed by suction filtration. The product is washed fourtimes with about 200 part portions of anhydrous diethyl ether. Afterdrying there is thus obtained 109 parts (97% of theory) ofbeta-methacrylyloxyethyltrimethylammonium cyclohexanesulfonate as awhite hygroscopic solid melting at 163-165 0.

EXAMPLE II Preparation of beta-methacrylyloxyethyltrimethylammoniam'methylsulfat'e A solution of 31.5 parts of freshly distilled dimethylsulfate in about 50 parts of anhydrous diethyl ether is added withstirring under anhydrous conditions over a period of two hours to acooled (ice/water bath) solution of 39.3 parts ofbeta-dimethylaminoethyl methacrylate in about 350 parts of anhydrousdiethyl ether. The reaction mixture is allowed to stand overnight atroom temperature and the solid product then removed by filtration. Afterdrying there is thus obtained 59.8 parts (84.5% of theory) of betamethacrylyloxyethyltrimethylammonium methylsulfate as a white,crystalline, hygroscopic solid. Upon recrystallization from methyl ethylketone, there is thus obtained 47.6 parts (80% recovery) of purifiedbeta methacrylyloxyethyltrimethylammonium methylsulfate.

Analysis-Calculated for Ciel-121N065: N. 4.94%. Found: N, 4.51%, 4.73%.

EXAMPLE III Preparation of betamethacrylylo:cyethyltrimethylammonz'amp-tolaenesulfonate A solution of 37.2 parts of methyl p-toluenesulfonatein about 140 parts of anhydrous diethyl ether is added slowly withstirring under anhydrous conditions to a cooled (ice/water bath)solution of 31.4 parts of beta-dimethylaminoethyl methacrylate in about210 parts of anhydrous diethyl ether. The reaction mixture is kept inthe ice/water bath for two hours after the addition is complete, thenallowed to stand at room temperature overnight. The solid is thenremoved by filtration and after washing with anhydrous diethyl etherthere is thus obtained 40.0 parts ofbeta-methacrylyloxyethyltrimethylammonium p-toluenesulfonate. Uponstanding an additional 15.5 parts of the quaternary deposits in thefiltrate. The total 55.5 parts cor responds to 81% of the theoreticalyield. The beta methacrylyloxyethyltrimethylammonium p-toluenesulfonateis a white, crystalline, hygroscopic solid soluble in water, methylethyl A. ketone, acetonitrile, and isopropyl alcohol. Uponrecrystallization from ethyl acetate, the purified betamethacrylyloXyethyltrimethylammonium p-toluenesulfonate is obtained aslong white needles melting at 128-129 C.

Analysis-Calculated for C16II25N05 S: N,4.08%; S, 9.31%. Found: N,4.08%, 4.11%; S, 9.36%, 9.56%.

EXAMPLE IV Preparation ofbis-(beta-methacrylyloryethyltrimethylammonium) sulfate An aqueoussolution of 3.5 parts of beta-methacrylyloxyethyltrimethylammoniumiodide is treated with excess aqueous silver sulfate solution. The whiteprecipitate or" silver iodide which forms immediately is removed byfiltration and the aqueous solution of thebis-(beta-methacrylyloxyethyltrimethylammonium) sulfate used directly inthe preparation of an acrylonitriie copolymer. To the aqueous solutionof the bis-quaternary sulfate is added 34.5 parts of acrylonitrile, 0.19part of ammonium persulfate and 0.38 part of sodium bisulfite and thesolution made up to a total of 500 parts with distilled water. The pH ofthe solution is adjusted to 3.3 by addition of sulfuric acid. Thepolymerization is started at 25 C. and the temperature allowed to raisespontaneously to 40 C. at which value it is maintained for two hours.After filtration, washing and drying there is obtained 11.2 parts of anacrylonitrile/bis-(methacrylyloxyethyltrimethylammonium) sulfatecopolymer as a white powder soluble in dimethylformamide from whichsolvent strong, self-supporting films exhibiting good receptivity toacid dyes can be solvent cast.

The present invention is generic to Z-methyleneacyloxyhydrocarbotrihydrocarboammonium salts of oxygen-containing strongsulfur acids, i. e., to quaternary ammonium salts of oxygencontainingstrong sulfur acids in which the four ammonium hydrogens are replaced byhydrocarbon radicals, no more than two of which are aromatic and one ofwhich has one and only one further substituent, and that aZ-methyleneacyloxy radical which is preferably free of active(Zerewitinoff) hydrogen and most preferably solely hydrocarbon otherthan the single carbonyloxy {-COO) group. Of the preferred class of themonomers of this invention, i. e., the2-methylenealkanoyloxyalkanetrihydrocarboammonium salts of theoxygen-containing strong sulfur acids, the most preferred because of thegreater availability of the requisite intermediates and also theproperties exhibited by the copolymers containing these units incombined form are the 2-methylenealkanoyloxyalkanetrihydrocarboammoniumsalts of sulfuric and hy drocarbosulfonic acids wherein the varioushydrocarbo groups are free of aliphatic unsaturation, i. e., saturatedaliphatic, including cycloaliphatic, aromatic, alkaromatic andaraliphatic, and preferably of no more than eight carbons each, with atleast two of the hydrocarbo groups bonded to the quaternary nitrogensbeing most preferably saturated aliphatic hydrocarbon of no more thanfour carbons each, including those compounds wherein two of themonovalent hydrocarbon radicals free of aliphatic unsaturation bonded tothe quaternary nitrogen may be together joined to form with saidquaternary nitrogen a heterocycle such as, for instance, a piperidylring. The new compounds of this invention having a long chainhydrocarbon radical, e. g., up to 18 carbons, on the tertiary aminonitrogen exhibit greater surface active properties both as monomers andin the polymers therefrom. These products, of which a typical example isbeta-acrylyloxyethyldimethyloctadecylammonium methylsulfate, aregenerally more diflicult to prepare and purify and for this reason arenot preferred although the special surface active properties theypossess make them of particular value in specific uses, e. g., inpigment dispersions, corrosion inhibitors.

Particular examples of the preferred compounds include those wherein the2 carbon carrying the terminal methylene group also carries a singlehydrogen, halogen, or monovalent hydrocarbon radical and the hydrocarbonradicals joining the acyloxy group to the quaternary nitrogen and thosebonded directly to the quaternary nitrogen are free of aliphaticunsaturation and at least two and most preferably all of the latter haveno more than four carbons each, such asbeta-acrylyloxyethyltriethylammonium methylsulfate,gamma-acrylyloxypropylethyldibutylammonium p toluenesulfonate, N(beta-acrylyloxyethyl)piperidinium methylsulfate; those wherein the 2carbon carrying the terminal methylenic group also carries a halogen ora hydrocarbon radical, preferably a short chain ali hatic hydrocarbonradical of no more than two carbons, and the various other substituentpositions of the molecule are as described above, e. g.,beta-methacrylyloxyethyltriethylammonium butylsulfate, gammalchloroacrylyloxypropyldimethylbenzylammonium m xylenesulfonate, betaethacrylyloxyethylmethylethylcyclohexylammonium ethylsulfate, and thelike. In the case of the polyvalent oxygen-containing strong sulfuracids, e. g., sulfuric acid, one or two of the2-methyleneacyloxyhydrocarbotrihydrocarboammonium radicals may be singlyionically bonded to the polyvalent anion. The compounds of the typewherein only one such quaternary nitrogen is so bonded are illustratedabove and in the examples. Included in the latter type of such compoundsare the his (beta methacrylyloxyethyltriethylammonium) sulfate ofExample IV, and like compounds.

This new class of monomeric quaternary compounds is represented by thefollowing structural formula:

wherein R is hydrogen, halogen, e. C1, or hydrocarbon, and is preferablyhydrogen or aliphatically saturated hydrocarbon of no more than twocarbons; R1 is a divalent hydrocarbon radical, preferably saturatedaliphatic of no more than four carbons; R2, R3, and R4 are similarlyhydrocarbon, preferably free of'aliphatic saturation and of no more thaneighteen carbons apiece with usually at least two and preferably all ofsaid R groups being of no more than eight carbons apiece and mostpreferably of no more than four carbons apiece, any two of which can betogether joined to form with the nitrogen a heterocyclic ring, e. g., apiperidyl ring; X is the negative anion, of valence n, of anoxygen-containing strong sulfur acid, preferably the sulfate orhydrocarbosulfonate anion; and n is an integer from 1 to 2. In thoseinstances wherein 'n is 1, the single negatively charged anion X is thatof a monobasic oxygen-containing These new monomers can be prepared inmany ways; for instance they can be prepared by simple ionicinterchange, using as starting materials the2-methyleneacyloxyhydrocarbotrihydrocarboammonium salts of the simplemonovalent inorganic acids, e. g., the quaternary halides, and reactingsuch compounds with salts of the oxygen-containing strong sulfur acidinvolved under ionic conditions. For instance, betaInethaorylyloxyethyltrimethylammonium p-toluenesulfonate can be preparedby reacting beta methacrylyloxyethyltrimethylammonium chloride with anaqueous solution of sodium ptoluensulfonate. The monomers of the presentinvention, wherein a polyvalent oxygen-containing strong sulfur acidanion is involved, can be prepared similarly. For instance, bis(-betamethacrylyloxyethyltrimethylammonium) sulfate can be prepared byreacting two moles of beta methacrylyloxyethyltrimethylammonium chloridewith one mole of sodium sulfate in aqueous solution, or, as illustratedin Example IV, by reacting silver sulfate with the correspondingquaternary iodide. However, since these methods depend upon an anioninterchange reaction which may not of necessity always be carried out tosuccessful completion, the monomeric products thereby obtainedaccordingly may have some unreplaced and undesirable quaternary ammoniumunits wherein the anion is that of the starting acid.

The simplest and most convenient method for preparing the monomers ofthis invention involves the direct reaction between the necessary2-methyleneacyloxyhydrocarbodihydrocarbo tertiary amine and therequisite uaternizing ester of the oxygen-containing strong sulfur acid.This type reaction is not only readily carried out with easily availableintermediates, but also avoids any possibility of having present in themonomer any of the less desirable quaternary ammonium monomers of otheracids. This quaternization reaction is generally and most convenientlycarried out at from 0 C. to room temperature, although lower and highertemperatures, e. from 5 C. up to 70 C. or higher can be used.Ternperatures above about 40 to 50 C. are generally to be avoidedbecause of th tendency of the monomers to polymerize under suchconditions. If it is desirable to operate at an elevated temperaturebecause of increased rate of reaction or other reasons, this tendency topolymerize may be diminished or eliminated by the addition of aconventional polymerization inhibitor that may be removed from thequaternary monomer by crystallization or other means prior topolymerization. The requisite Z-methyleneacyloxyhydrocarbodihydrocarbotertiary amine and the quaternizing ester of the oxygen-containingstrong sulfur acids are usually reacted in essentially equimolarproportions either in bulk or preferably in the presence of an inertsolvent.

acvmeei Slight excesses of either reactant can be used but are generallyto be avoided because of the greater difiiculty encountered in purifyingthe products.

The preferred solvents for carrying out the quaternization reaction arethose in which the quaternary oxygen-containing strong sulfur acid saltis relatively insoluble, such as, for example, the lower hydrocarbonethers, e. g., diethyl ether, dibutyl ether; the halogenatedhydrocarbons, e. g., the polychlorinated hydrocarbons such aschloroform, carbon tetrachloride, tetrachloroethane, and the like.Generally water is to be avoided in the quaternization reaction becauseof difiiculties encountered in obtaining the desired quaternary monomerin good crystalline form from systems which are at all aqueous. Thus, asillustrated specifically by Example II, a typical quaternary monomer ofthis invention, e. g., betamethacrylyloxyethyltrimethylammoniummethylsulfate is conveniently prepared by reacting equimolar proportionsof dimethyl sulfate with beta-dimethylaminoethyl methacrylate insolution in diethyl ether at room temperature under anhydrousconditions. The quaternization reaction in general appears essentiallycomplete in 48 hours, and the desiredbeta-methacrylyloxyethyltrimethyl-ammonium methylsulfate separates fromthe reaction mixture as a white powder which is conveniently removed byfiltration and subsequently dried.

The new quaternary monomers of this invention are useful in thepreparation of quaternary polymers and copolymers as given in greaterdetail in the previously identified copending application of Barney.These new quaternary monomers can be polymerized by any of the meanspreviously recognized for the polymerization of addition type monomers,including thermal polymerization as well as polymerization initiated byionic and free radical type generating catalysts such as the peroxidesand hydroperoxides, azo type initiators, the various redox systems, andthe like, already well known in the art. Polymerization andcopolymerization of these new monomers may be carried out in solution orsuspension with the latter, e. g., emulsion polymerization, beingpreferred.

Suitable examples of the addition polymerizable monomers which may becopolymerized with the members of this new class of quaternary monomersinclude those addition polymerizable mono ers of one ethylenicunsaturation such as olefins, e. g., isobutylene; acrylyl and alkacrylylcompounds, e. g., acrylic, haloacrylic, and methacrylic acids, esters,nitriles, and amides, for example, acrylonitrile, butyl acrylate,methacrylic acid, alpha-chloroacrylic acid, the aminoalkyl acrylates, e.g., beta-diethylaminoethyl methacrylate; vinyl and vinylidene halides,e. g., vinyl chloride, vinylidene chloride, vinyl carboxylates, e. vinylacetate; vinyl aryls, e. g., styrene and other vinyl derivatives such asmethyl vinyl ketones, vinylpyridines, vinylisobutylene ethers. Thepolymers from the monomers of the present invention can contain incombined form polymerizable compounds containing a plurality ofethylenic double bonds including those having conjugated double bondswhich are furthermore both terminal ethylenic double bonds such asbutadiene, z-chlorobutadiene, and compounds containing two or moreethylenic double bonds which are isolated with respect to each other,including, for instance, the acrylic and substituted acrylic esters ofpolyhydric alcohols, e. g., ethylene glycol dimothacrylate;polymerizable compounds having one ethylenic group conjugated with acarboxylic group, e. g., diallyl maleate, and compounds which have notconjugation of the polymerizable ethylenic groups, e. g.,divinylsuccinate. The preferred copolyrners from the monomers of thisinvention are those containing in combined form those additionpolymerizable monomers having a single terminal methylene group joinedby an ethylenic double bond to its neighboring carbon, i. e., compoundscontaining the terminal group CH2 C The quaternary ammonium monomers ofthis invention are of use in the preparation of the above-describedpolymers and copolymers. In the preparation of copolymers the quaternaryammonium monomers of this invention show distinct advantages in allowingcareful control of the amount of quaternary units introduced into thepolymer, avoidin the presence of any unquaternized tertiary amino unitsor unreacted quaternizing agent in the polymer, and permitting thepreparation of copolymers of better physical properties because of therelatively easy purification of all the component comonomers prior topolymerization. The new quaternary ammonium monomers of this inventionare not only useful in the preparation of films and fibers, but they arealso useful as bacteristatic agents, humectants, and organicintermediates.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom. The invention is not limited to the exact details shown anddescribed for obvious modifications will occur to those skilled in theart.

What is claimed is:

1. beta Methacrylyloxyethyltrimethylammonium methyl sulfate.

2. A. methacrylyloxyethyltrimethylammonium sulfate.

3. A methacrylyloxyethyltrimethylammonium alkylsulfate in which sulfatethe alkyl group is of up to four carbon atoms.

4. A methacrylyloxyethyltrimethylammonium salt of an oxygen-containinstrong sulfur acid.

5. A methacrylyloxyalkyltrialkylammonium sulfate in which sulfate eachalkyl group is of up to i carbons.

6. A methacrylyloxyalkyltrialky1ammonium salt of an oxygen-containingstrong sulfur acid in which salt each alkyl group is of up to fourcarbon atoms.

7. A quaternary ammonium salt of an oxygencontaining strong sulfur acidin the cation of which salt the four valences of quaternary nitrogen aresatisfied by hydrocarbon radicals of not more than eight carbon atomseach no more than two of which are aryl and only one of which has analpha-methylenealkanoyloxy substituent of up to four carbon atoms.

8. A quaternary ammonium salt of an oxygencontaining strong sulfur acidin the cation of which salt the four valences of the quaternary nitrogenare satisfied by hydrocarbon radicals of not more than eight carbonatoms each not more than two of which are aryl and only one of which hasan alpha-methyleneacyloxy substituent.

9. A quaternary ammonium salt of an oxygen containing strong sulfur acidin the cation of which salt the four valences of the quaternary nitrogenare satisfied by hydrocarbon radicals free from aliphatic unsaturationand of no more than eight carbon atoms each, at least two of nitrogenare satisfied by saturated aliphatic hy- 10 drocarbon radicals of nomore than four carbon 10 atoms each, one and only one of which aliphatichydrocarbon radicals has an alpha-methylenealkanoyloxy substituent of nomore than four carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,103,265 Scott Dec. 28, 1937 2,138,763 Graves Nov. 29, 1938

1. BETA - METHACRYLYLOXYETHYLTRIMETHYLAMONIUM METHYL SULFATE.